Builders for synthetic detergent compositions based on carboxyethyl derivatives of polyalcohols

ABSTRACT

Builders for use in synthetic detergent compositions are described; said builders comprising compounds of the class of carboxyethyl ethers of selected polyalcohols and their salts.

EJnited States Patent Tessler et al. 1 June 13, 1972 BUILDERS FOR SYNTHETIC R f r n Cited DETERGENT COMPOSITIONS BASED ON CARBOXYETHYL DERIVATIVES UNITED STATES PATENTS 0 POLYALCOHOLS I 2,311,008 2/1943 Tucker ..252/89 [72] Inventors: Martin M. Tessler, Edison; Morton W. Ru- 3459'67o 8/1969 Caner Jr 52/89 tenberg North plainfield both OfN J 2,401,607 6/1946 Bruson 260/4656 2,974,134 3/1961 Pollitzer ..252/89 Assignee: National Starch and Chemical p 3,082,257 3/1963 Karabinas et al. ..252/89 lion, New York, N.Y.

22 Filed; Feb, 25 1971 Primary Examiner-Leon D. Rosdol Assistant ExaminerW. Schulz [21] Appl' No" Att0rney.lames&Franklin 52 US. c1 ..252/89, 260/484 [57] ABSTRACT 51 1111.0. [58] Field of Search ..252/89; 260/465.6, 484 P, 484 B BuilderS for use In Syntheflc detergent composmons are described; said builders comprising compounds of the class of carboxyethyl ethers of selected polyalcohols and their salts.

3 Claims, No Drawings BUILDERS FOR SYNTHETIC DETERGENT COMPOSITIONS BASED ON CARBOXYETHYL DERIVATIVES OF POLYALCOHOLS This invention relates to synthetic detergent compositions containing a compound of the class of carboxyethyl ethers of selected polyalcohols and their salts as a detergent builder, said compositions being useful in aqueous washing solutions. In a further aspect, the invention relates to an improved process for washing fabrics in an aqueous medium containing said detergent composition.

Detergent builders, as is well known to those skilled in the art, are used to improve the detergency effectiveness of synthetic detergent compositions and thereby improve their whitening powers. Polyphosphate compounds such, for example, as sodium tripolyphosphate, have been in long use as builders particularly because of their relatively low cost and their utility in increasing the whitening powers of detergent composin'ons containing them. It is also well known, however, that the presence of these polyphosphates tends to enhance the growth of algae in lakes and rivers to a significant degree which is sufficient to undesirably upset the natural ecology of these waters. With the recent governmental emphasis on environmental pollution control, phosphate pollution of water, as caused by the dumping of phosphate containing wash waters, is being closely watched and studied. There is increasing pressure to lower or discontinue their usage completely in detergent compositions in favor of non-phosphate builders.

The manner in which detergent builders improve the whitening powers of detergent compositions is related to a combination of factors. Thus, builders are believed to take part in the detergency system by such factors as emulsification of soil particles, solubilization of water-insoluble materials, promoting soil suspension in the wash water so as to retard soil redeposition, sequestering of metallic ions, and the like.

Among the important properties that must be exhibited by compounds employed as builders are included: the ability to increase the whitening power of the detergent composition, non-toxicity, compatibility with the various components and additives of conventional detergent compositions, and stability with respect to hot, alkaline aqueous mediums and bleaching agents.

It is the prime object of this invention to provide a nonphosphate builder which is particularly effective in increasing the whitening power of synthetic detergent compositions. his a further object of this invention to provide a method for washing fabrics in a medium containing detergent comprising a non-phosphate builder.

Various other objects and advantages of this invention will be apparent from the following description thereof.

We have now found that compounds of the class of carboxyethyl ethers of pentaerythritol, dipentaerythritol, tripentaerythritol, and gluconic acid, and salts thereof, are useful as detergent builders and impart marked improvements in the whitening power of synthetic detergent compositions. We have also found that the use of synthetic detergent compositions containing such a derivative in accordance with this invention, results in washed fabrics having a whiteness substantially equal to fabrics washed with a comparable detergent composition containing a conventional polyphosphate builder.

Thus, a compound typical of the class of compounds described herein for use as a builder comprises either a pentaerythritol, dipentaerythritol, tripentaerythritol, or gluconic acid, wherein all or at least about 20 percent of the hydroxyl groups of the starting compound have been cyanoethylated and the resultant cyanoethylated derivative has been hydrolyzed. The carboxyethyl ether of Pentaerythritol (fully converted) corresponds to the structure:

Also useful herein as the novel builders of this invention are the water-soluble, alkali metal salts of the described carboxyethyl derivatives of polyalcohols. In general practice, the use of alkali metal salts is preferred. The water solubility of these salts should be such that at least about 0.1 grams of the salt dissolves in 100 grams of water at 25 C. It is also preferred to formulate the detergent composition so that the pH of the washing solution, i.e. the aqueous medium containing the detergent composition, ranges from about 7 to 13.

The described compounds useful as builders herein are most conveniently obtained by means of a chemical cyanoethylation reaction and hydrolysis reaction of the resultant product employing either pentaerythritol, dipentaerythritol, tripentaerythritol or gluconic acid as the starting material. These reactions may, preferably, be carried out essentially as described in U.S. Pat. No. 2,401,607, issued June 4, 1946. In this procedure the selected polyalcohol is suspended in water and an aqueous solution of a base such as potassium hydroxide is then added thereto in order to assure an alkaline reaction medium. Acrylonitrile is thereafter slowly added to the aqueous polyalcohol mixture in an amount that will vary with respect to the degree of cyanoethylation of the starting material which is desired. For example, for complete or 100 percent cyanoethylation of the hydroxyl groups of the starting material, about 1 mole of acrylonitrile is required for each equivalent weight of the polyalcohol. For 50 percent cyanoethylation of the hydroxyl groups, about one-half mole of acrylonitrile is required, etc. It is to be understood that where 100 percent, 50 percent, or other percentage of cyanoethylation is given herein, such percentages assume complete reaction efficiency. It is to be realized that in practice reaction efficiency is less, and the actual percent cyanoethylation will be less than the given figure. In a typical procedure, the acrylonitrile is added slowly to the aqueous polyalcohol mixture, and the resultant mixture is stirred for about 1 hour at room temperature and 1.5 hours at 60 C. Ordinarily, temperatures from about 0 to 70 C. can be utilized with time periods ranging from about 1 to 16 hours. At the completion of the condensation reaction the pH of the reaction medium is thereafter adjusted to about 6 to 8, preferably with dilute hydrochloric acid, but other acids such as sulfuric or phosphoric may likewise be used for this purpose. The water which is employed as the reaction medium is removed by distillation. The small amount of inorganic salts produced during the reaction may be removed by dissolving the resultant nitrile intermediate in acetone and filtering the mixture in order to separate the insoluble inorganic salts. It has been found that these salts do not interfere with the subsequent hydrolysis of the nitrile and, if desired, these inorganic salts produced herein may conveniently be separated together with the salt produced during the hydrolysis of the nitrile intermediate.

The nitrile intermediate is thereafter hydrolyzed in an aqueous, acidic medium. For example, to a given quantity of the nitrile, twice the calculated theoretical amount of acid necessary for hydrolysis is added thereto and the mixture is slowly heated to about 70 C. Use of concentrated hydrochloric acid is preferred but other acids such as sulfuric acid may likewise be used herein. The temperature of the reaction mixture is maintained between about 70 to C. for a period of 3 hours and thereafter raised to C. for a period of one-half hour. The reaction mixture is then cooled and evaporated under reduced pressure to dryness. The resultant carboxyethyl derivative (usually in oil form) is dissolved in acetone or similar organic solvent and the acetone-insoluble salts, ammonium chloride if hydrochloric acid is used in the hydrolysis, as well as the salts from the condensation reaction if not previously removed, are removed by filtration. The acetone is removed by distillation. The resultant salt-free product may be converted into its alkali metal salt form by adding it to water and adding sufficient concentrated aqueous base such, for example, as a 50 percent, by weight, aqueous solution of sodium hydroxide, to raise the pH of the mixture to be within a range of 9 to 12. Excess water is removed by distillation to yield the product in crystalline salt form.

Variations in the described procedure for the cyanoethylation of the polyalcohols as well as the hydrolysis of the nitrile intermediate are readily found in the literature and may easily be utilized herein.

It is an advantage of the present builders that in addition to enhancing the whitening power of detergents in a degree comparable to sodium tripolyphosphate, the present builders are fully compatible with and stable towards bleaching agents commonly used in conventional clothes washing. Thus, the detergent builders of the present invention neither lose their whitening power in the presence of bleaches such as chlorine bleaches nor do they interfere with or impair the function of the bleaches themselves.

in utilizing these detergent builders, they are most conveniently admixed with a selected detergent composition in place of (either partially or entirely) the conventional builder as, for example, sodium tripolyphosphate previously used therein. Ordinarily, conventional, commercially available detergent compositions will contain from less than about 1 percent up to about 60 percent or more of builder, based on the weight of the total detergent composition solids, and it is comprehended that the present novel builders may be utilized in the same concentrations. Concentrations of builder within the range of from about 20 to 60 percent, based on the weight of the total detergent composition solids, are preferred, however, since builder concentrations of less than about 20 percent will usually result in insufficient whitening power. In utilizing the novel builders it is to be understood that the detergent composition incorporating the builder can be prepared for use in any of several physical forms as, for example, granular, flake, bar, tablet and liquid forms.

If desired, however, the selected builder of our invention can be added to the wash media separately with equal effect. The detergent composition, in addition to the detergent and builder, may also contain a number of other ingredients. Thus, the detergent composition may contain any of the usual types of fillers, such as sodium sulphate, sodium carbonate, and the like. Anti-corrosion agents such as sodium silicate and sodium metasilicate as well as optical brighteners, soil anti-redeposition agents, and enzymes may also be included, ifdesired.

The builder described herein may be utilized in a detergent composition comprising any of the synthetic organic detergents which are commonly used for aqueous washing purposes. The detergent may be of the anionic, non-ionic, cationic, or amphoteric type or character. Further description of detergents such as are useful in the detergent compositions comprehended herein are readily found in the literature, as for example, in U.S. Pat. No. 2,755,252 entitled Partially Acetylated Polyvinyl Alcohol as a Soil-suspending Agent" issued July 17, 1956 and U.S. Pat. No. 3,459,670 entitled Builders for Synthetic Detergents issued Aug. 5, 1969. It is clear that the particular detergent used in the detergent compositions of the present invention is not critical except that it should be generally useful in emulsifying and detergent applications.

The actual use of the detergent builders of this invention comprises the use of the resultant detergent composition (detergent, builder and optional additives) in conventional concentrations, i.e. from about 0.1 to 0.2 percent, based on the weight of the wash water, in a conventional washing procedure, ordinarily making use of agitation and temperatures ranging up to about l80 F. Use of the detergent composition in this manner has been found to enhance the whitening power of the wash medium, and the washed fabrics have been found to be significantly brighter.

The invention is further illustrated in connection with the following examples in which all parts given are by weight unless otherwise noted. The water employed in the wash media as well as the rinses in all of the following examples was adjusted to have a hardness of about 150 ppm measured as calcium carbonate.

EXAMPLE 1 This example illustrates a typical preparation of a completely cyanoethylated pentaerythritol and its subsequent hydroly- 515.

About 34 grams of pentaerythritol (0.25 moles) and 2 grams of a 40 percent, by weight, aqueous solution of potassium hydroxide were added to 50 grams of water. The mixture was stirred and 53 grams of acrylonitrile l.0 moles) were slowly added thereto. The resultant mixture was stirred at room temperature for 1 hour and at 60 C. for an additional 1% hours. The pH of the mixture was lowered to 6.8 with dilute hydrochloric acid thereafter, and the water removed by distillation under reduced pressure. The resultant organic intermediate was dissolved in 200 milliliters of acetone and the insoluble salts were separated by filtration. The acetone was removed by distillation to yield 84.3 grams of the purified cyanoethylated pentaerythritol product, tetra( cyanoethoxymethyl) methane.

Hydrolysis of the thus prepared product was carried out by preparing a mixture of 40 grams of the tetra(cyanoethoxymethyl) methane and 92 grams of concentrated hydrochloric acid. The mixture was slowly heated to 70 C. and the temperature was thereafter maintained between 70 and C. for a period of 3 hours and then raised to about C. for an additional 1 hour period. The mixture was stirred continuously throughout the heating periods. At the end of the heating periods, the reaction mixture was cooled and evaporated to dryness under reduced pressure. The resultant waterless product was dissolved in 300 milliliters of acetone, and the insoluble ammonium chloride was removed by filtration. The acetone was subsequently removed by distillation to yield 48.5 grams of a purified product in the form of a viscous oil. The fully converted product may be represented by the following formula:

0 i C CH2 4 The sodium salt of the product was prepared by dissolving it in water and adjusting the pH of the solution with 50 percent, by weight, aqueous sodium hydroxide to about 12, and thereafter evaporating the alkaline solution to dryness. A white, crystalline salt was obtained.

EXAMPLE II This example illustrates the preparation of several cyanoethylated dipentaerythritol compounds and their subsequent hydrolysis.

To a mixture of 50 grams of water and 2 grams of a 40 percent, by weight, aqueous solution of potassium hydroxide was added 42.3 grams of dipentaerythritol (0.167 mole). The mixture was stirred and 53 grams of acrylonitrile (1.0 mole) were slowly added thereto. The resultant mixture was stirred at room temperature for 1 hour and at 60 C. for an additional 1% hours. The pH of the mixture was lowered to 8.0 with dilute hydrochloric acid thereafter, and the water removed by distillation under reduced pressure yielding 94.9 grams of crude, essentially completely cyanoethylated dipentaeryrithritol.

Hydrolysis of thus-prepared product was carried out by preparing a mixture of 40 grams of the crude cyanoethylated dipentaerythritol and 84 grams of concentrated hydrochloric acid. The mixture was heated to between 70 to 80 C. for a period of 3 hours and then heated at 100 C. for an additional k hour period. The mixture was stirred continuously throughout the heating periods. At the end of the heating periods, the reaction mixture was cooled and evaporated to dryness under reduced pressure. The ammonium chloride and other inorganic salts were removed by washing the organic product with two 100 gram portions of water. The washed product was dried by heating under reduced pressure. The

yield of the carboxyethyl ether of dipentaerythritol in the form of a yellow oil was 43.2 grams.

The sodium salt of the thus-prepared derivative was obtained by suspending it in water and adjusting the pH of the mixture with 50 percent, by weight, aqueous sodium hydroxide to about 12, and thereafter evaporating the alkaline solution to dryness. A white crystalline salt was obtained.

Three additional carboxyethyl ethers of dipentaerythritol of lesser substitution (70, 50 and 25 percent cyanoethylation) were prepared essentially according to the procedure described above except that the amount of acrylonitrile employed was reduced to 37.1, 26.5 and 13.3 grams, respectively. The amount of concentrated hydrochloric acid used for the hydrolysis of the cyanoethylated intermediates was correspondingly reduced to 58.8, 42.0 and 21.0 grams, respectively.

EXAMPLE III This example illustrates the preparation and evaluation of a typical detergent composition containing a builder of this invention.

The detergent composition was prepared by blending together the following ingredients:

Sodium dodecylbenzene sulfonate (detergent) 25 parts 100% CE Pentaerythritol" (builder) 20 parts Sodium sulfate (filler) 44.5 parts Sodium silicate (corrosion inhibitor) parts Sodium carboxymethyl cellulose (soil anti-redeposition agent) 0.5 parts For purposes of this invention, the abbreviation 100% CE Pentaerythritol will represent 100% carboxyethylated pentaerythritol, sodium salt. Other similar abbreviations will be self-explanatory.

Two additional detergent compositions were prepared for comparison purposes which were identical to the composition described above, except that one composition contained 20 parts of sodium tripolyphosphate, a well-known, commercially used builder, and the remaining composition contained 20 parts of pentaerythritol, each in plate of the 100 percent carboxyethylated pentaerythritol.

A series of aqueous wash media were prepared by admixing 1.5 grams of each of the three above described detergent compositions, respectively, to 1,000 milliliters of water. Swatches (3 by 7 inches) of undyed cotton were soiled in a small test area measuring about 1% inches in diameter by wiping the skin of the brow and neck of each member of a test panel of 10 male individuals, respectively, in an effort to approximate the soiling of fabrics which takes place in day-to-day situations. Each wash load contained a swatch from each panel member. The washes were conducted in a washing apparatus sold by U.S. Testing Company and called a Terg-o-Tometer with the temperature of the wash media at 120 F. The washed swatches were rinsed and ironed between two pieces of white fabric so as to eliminate any dirt transfer from the iron. Reflectance readings indicating the degree of whiteness of the test area were then made with a Photovolt Corporation Photoelectric Reflectance Meter, Model 610. Thereafter, the test procedure including the soiling of the identical test areas of each swatch, respectively, was repeated four times. Reflectance readings of the test swatches with and without soiling before washing were also obtained and the readings were approximately inserted into the following calculation in order to obtain the Detergency of the test composition.

Detergency (R R (10O)/(R R wherein:

R reading of washed, soiled swatch R reading of unwashed, soiled swatch R reading of unsoiled swatch.

Table 1 summarizes the results obtained with the various indicated wash media. Each of the Detergency values given in the table is the mean of 10 swatches.

TABLE 1 Detergency after wash No.

Test Composition 5 Using 100% CE Pentaerythritol 84 76 75 5 9 65 Using Sodium tripolyphosphate 85 69 64 64 Using Pentaerythritol 75 70 58 57 57 It is seen from the above data that the detergent composition containing a novel builder of this invention exhibits Detergency values comparable to those achieved with a composition containing a convention, commercially-used builder, namely sodium tripolyphosphate. The low Detergency values obtained with the composition containing pentaerythritol show the underivatized polyalcohol to be undesirable for use as a builder.

EXAMPLE IV This example illustrates a series of detergent compositions each containing a builder of progressively less substitution.

Table 11, below summarizes the Detergency of the various compositions when subjected to the evaluation described in the previous example.

TABLE II Detergency after wash No. Composition 1 2 3 4 5 A 82 71 75 74 77 B 78 79 68 79 68 C 85 72 72 65 D 83 77 83 67 61 E 62 59 47 36 36 The above data clearly indicate that suitable Detergency values are obtained with each of the novel builders of this invention employed herein. The Detergency values obtained with the composition containing no builder, Composition E, are given for comparison purposes.

EXAMPLE V This example illustrates a typical detergent composition of this invention being used in a wash media containing a chlorine releasing bleach.

Two detergent compositions were prepared: one composition was identical to Composition B described in Example IV, and the other composition employed sodium tripolyphosphate in place of the novel builder. The compositions were evaluated for Detergency as described in Example 111 with the sole exception that the wash media had added thereto a chlorine-releasing bleach in a concentration equivalent to about 0.03% by weight of active chlorine, as recommended by i the manufacturer.

% Detergency after wash No.

Composition 1 2 3 4 5 Using sodium tripolyphosphate 95 I01 1 99 iOl Using 70% CE Dipentaerythritol 90 93 101 95 95 EXAMPLE VI This example illustrates a detergent composition wherein the builder ingredient is comprised of a combination of sodium tripolyphosphate and a novel builder of this invention.

Two detergent compositions were prepared containing ingredients as indicated below:

Table Ill, below, summarizes the Detergency of these compositions when subjected to the test procedure described in Example Ill.

TABLE II] Detergency after wash No. Composition 1 2 3 4 5 The above data clearly indicate the excellent compatibility of a typical builder of this invention with a known, conventiorial builder, namely sodium tripolyphosphate.

EXAMPLE VII This example illustrates the utility of additional detergent compositions containing a novel builder of this invention.

A series of detergent compositions were prepared containing ingredients as described below:

Composition parts) A B CD Sodium dodecylbenzene sulfonate 25 25 25 25 l00% CE Gluconic acid l0 0 70% CE Tripentaerythritol 4O 60 Sodium sulfate 44.5 54.5 2454.5 Sodium silicate l0 l0 l0 [0 Sodium carboxymethyl cellulose 0.5 0.5 0.5 0.5

An evaluation of the above compositions by means of the Detergency test showed these compositions to exhibit Detergency values comparable to the values obtained with the compositions described in the previous example.

Summarizing, it is seen that this invention provides a novel, effective class of non-phosphate builders for use in preparing detergent compositions.

It is to be noted that although emphasis has been placed in describing this invention in connection with the washing of fabrics, the detergent compositions comprehended within the scope of this invention are likewise useful for all washing purposes including, for example, dishwashing, floorwashing, carwashing, and the like. Variations in materials, proportions, and procedures may be made without departing from the scope and spirit of this invention as defined by the following claims.

We claim:

1. A detergent composition consisting essentially of a synthetic organic detergent, and in combination therewith as a builder of about 1 to about 60 percent, based on the weight of the total detergent composition solids, of a compound selected from the group consisting of carboxyethyl ether of pentaerythritol, carboxyethyl ether of dipentaerythritol, carboxyethyl of tripentaerythritol, carboxyethyl ether of gluconic acid, and water-soluble salts thereof.

2. The detergent composition of claim I, wherein there is also present in minor amounts a an optical brightener, a corrosion inhibitor, and a soil anti-redeposition agent.

3. A process for removing soil from a fabric which comprises washing said fabric in an aqueous medium containing a detergent composition consisting essentially of a synthetic organic detergent, and in combination therewith as a builder about 1 to about 60 percent, based on the weight of the total detergent composition solids, of a compound selected from the group consisting of carboxyethyl ether of pentaerythritol, carboxyethyl ether of dipentaerythritol, carboxyethyl ether of tripentaerythritol, carboxyethyl ether of gluconic acid, and water-Soluble salts thereof. 

2. The detergent composition of claim 1, wherein there is also present in minor amounts a an optical brightener, a corrosion inhibitor, and a soil anti-redeposition agent.
 3. A process for removing soil from a fabric which comprises washing said fabric in an aqueous medium containing a detergent composition consisting essentially of a synthetic organic detergent, and in combination therewith as a builder about 1 to about 60 percent, based on the weight of the total detergent composition solids, of a compound selected from the group consisting of carboxyethyl ether of pentaerythritol, carboxyethyl ether of dipentaerythritol, carboxyethyl ether of tripentaerythritol, carboxyethyl ether of gluconic acid, and water-soluble salts thereof. 